As an example of an airbag for protecting an occupant in case of a vehicle collision or the like, Japanese Unexamined Patent Application Publication No. 2004-244006 discloses an airbag having a left airbag section and a right airbag section which are inflated on the left side and the right side in front of the occupant, respectively, and adapted to be inflated by a common inflator.
The airbag is folded and stored in a case, and covered by a lid or an instrument panel. When the inflator (gas generator) is activated to jet gas upon vehicle collision, the airbag pushes and opens the lid or the instrument panel and is inflated in front of the occupant.
On the surface of the inflated airbag facing the occupant, a recess extends between a left chamber and a right chamber, from the upper surface of the airbag to the lower surface of the airbag.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-244006
In the airbag disclosed in the above-described Japanese Unexamined Patent Application Publication No. 2004-244006, since the recess has a depth of about 280 to 480 mm, the surface area of the airbag is large. Therefore, a panel having a large area (a large amount of cloth) is necessary for forming the airbag and the material cost is increased.